Health Library

Food Poisoning

What is food poisoning?

Food-borne illnesses affect millions of Americans each year. Many people who think they have the "stomach flu" or a virus are really victims of a mild case of food poisoning, caused by bacteria and viruses found in food. Particularly vulnerable to these infections are young children, the elderly, pregnant women (because of the risk to the fetus), and people with chronic or serious illnesses, whose immune systems are already weakened.

What causes food poisoning?

Most food-borne illnesses are caused by eating food containing certain types of bacteria or viruses. After a person has eaten these foods, the microorganisms continue to grow in the digestive tract, causing an infection. Foods can also cause illness if they contain a toxin or poison produced by bacteria growing in food.

Several different kinds of bacteria can cause food poisoning. Some of the common bacteria include the following:

Salmonella and Campylobacter. Normally found in warm-blooded animals, such as poultry and reptiles, also may be present in raw meat, poultry, eggs, or unpasteurized dairy products.

Clostridium perfringens. May be present in raw meat, poultry, eggs, or unpasteurized dairy products, as well as in vegetables and crops that come into contact with soil. Infection may occur when soups, stew, and gravies made with meat, fish, or poultry are stored improperly or left unrefrigerated for several hours.

Staphylococci. Occur normally on human skin and in the nose and throat. These bacteria may be transmitted to food when handled by someone with the bacterium.

Escherichia coli (E. coli). Found in the intestines of healthy cattle. An infection is caused by eating undercooked beef (especially ground beef) or unpasteurized milk.

Hepatitis A and other viral diseases may be passed through the hands of infected people onto the hands of food handlers or into sewage. Shellfish and other foods which may have been exposed to sewage-contaminated water can transmit these viral diseases.

Botulism is a rare but deadly form of food poisoning caused by Clostridium botulinum, which is found almost everywhere, including in soil and water. Low acid foods, such as meat, fish, poultry, or vegetables, that are improperly canned or improperly preserved may be breeding grounds for this bacteria. Raw honey and corn syrup can also cause botulism in infants. Babies under the age of 1 year old should never be given honey or corn syrup for this reason.

What are the symptoms of food poisoning?

Most cases of food poisoning mimic gastroenteritis, and many people with mild cases of food poisoning think they have the "stomach flu." However, the onset of symptoms is usually very sudden and abrupt, often within hours of eating the contaminated food. The following are the most common symptoms of food poisoning. However, each individual may experience symptoms differently. Symptoms may include:

Abdominal cramps

Watery and/or bloody diarrhea

Nausea and vomiting

Headache

Fever

Abdominal distention and gas

The symptoms of food poisoning may resemble other medical conditions or problems. Always consult your doctor for a diagnosis.

Treatment for food poisoning

Most mild cases of food poisoning are often treated as gastroenteritis, with fluid replacement and control of nausea and vomiting being the primary focus. Antibiotics may actually make the situation worse. However, in serious cases of food poisoning, hospitalization may be necessary. Be sure to see your doctor if you're unable to keep even fluids down or your symptoms are persistent.